The invention relates to a receiver lock for a box hitch in general, and more specifically to an integral cam locking pin that replaces a conventional hitch pin and clip to prevent unauthorized removal.
Previously, many types of locks for hitches have been used to provide an effective means to protect a trailer that has been attached to a vehicle from unauthorized removal. Prior art has provided various dead bolt hitch locks that are made in two pieces which utilize a key to lock the parts together to make the closure. Other attempts to lock a trailer to a towing apparatus include padlocks, chains, cables and the like, or in the case of a large trailer attached with a fifth wheel, a hitch lock is used on a coupler surrounding a pin which excludes attachment by a vehicle.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however the following U. S. patents are considered related:
Villalon, Jr. in U.S. Pat. No. 5,937,679 teaches an anti-theft device for a trailer coupler which covers a receptacle to a coupler, thus preventing insertion of a hitch ball or other towing means. Locking is achieved by using a retaining member and a lock housed in the body of the device. A second embodiment includes a lever independent of the retaining member held in place with a lock.
Kravitz in U.S. Pat. No. 5,735,539 teaches a trailer hitch locking device using a connection tightening mechanism with a bridge element, and a spaced pair of flanges secured to a projection from the bridge element. The elements straddle one of the components and as the flanges are connected to the components they engage a different component thereby tightening a telescopic connection.
U.S. Pat. No. 5,632,501 of Jackson is for a self-latching trailer coupler for use with a ball head post. The coupler includes a housing having a receiving socket with a latching member within the rear of the housing and is adapted to move between a latched and unlatched position. The latch member is guided along a path using guide pins and slots, and downward force automatically rotates the latch to an engaged position. A self-actuated locking device is provided for locking the latching member, and a locking lever is used for releasing the device.
Smith discloses in U.S. Pat. No. 5,441,395 a hitch lock assembly that is attached to a trailer hitch. The lock uses a pair of lock pin members operable with a padlock member to provide means for securing the hitch bail latch to the ball. Each lock pin is of steel rod construction and has a vertical section mountable within aligned holes in the hitch housing. The padlock member is removed from the interconnected lock pin to achieve an unlatched condition.
U.S. Pat. No. 4,730,468 issued to Becker is for an anti-theft device for semi-trailers using a cylindrical landing gear. A pin with an elongated head is inserted through a hole in the landing gear and is comprised of a cog that extends outward from a pin that is attached through the center of the pin to a circular keyway lock. When the cog is rotated outward, as rotated by the lock, the pin cannot be removed from the hole, therefore leaving the landing gear extended, and thereby preventing removal of the trailer by a semi-truck tractor.
For background purposes and as indicative of the art to which the invention is related reference may be made to the remaining citing issued to Sanders in U.S. Pat. No. 5,344,174.
The use of trailer hitches on vehicles such as automobiles, pick-up trucks and light utility vehicles has increased in popularity over the years and has been readily accepted specifically with the utilization of a hitch with a box-end receiver. The advantages of a box-end hitch permits hitches to be added to a vehicle using aftermarket equipment, and the fact that the design permits a ball mount to be removable is extremely advantageous as it does not leave the hitch extending beyond the bumper when not in use. The ball mount is installed by simply sliding its square shank into a rectangular opening in the box end hitch and it is held in place with a hitch pin, which is usually a rod beveled on one end with the other end bent in an L-shape. A pair of holes are aligned in both the hitch and the ball mount which allows the hitch pin to be inserted and then retained with a hairpin clip.
Since this box-end hitch system is efficient and has been in use almost universally, the primary object of the invention is to replace the L-shape pin with a key actuated locking pin that when secured in place prevents removal of the ball mount entirely and the trailer attached thereto. Attempts in the past for this type of replacement pin have used two separate parts that operate satisfactorily, however they are subject to loss or misplacement and require alignment and manual manipulation to install.
An important object of the invention is that the locking pin is installable with one hand as the pin is simply inserted in the aligned holes in the hitch and ball mount and the key is rotated and removed.
Another object of the invention is the fact that no tools are required to install the pin as is the case with mechanical fasteners used in conjunction with padlocks and the like.
Still another object of the invention is that the pin is extremely secure, as it is difficult to breach the lock""s integrity since the pin is constructed of a solid piece of hardened tool steel and only the head of the pin and the outside end of the lock are visible when installed. The lock itself is secured to the pin with a set screw and the set screw access hole is filled with epoxy; further, its position is almost inaccessible when the pin is installed.
Yet another object of the invention is that the pin has a rounded end for ease of insertion into the mating holes without visual communication. The operator may reach under the vehicle and by feel insert the pin into the holes since the shape permits the pin to self align.
A further object of the invention is that the lock is protected by a resilient protective cap, thus preventing the lock from freezing, moisture, rust, corrosion, or clogging with debris when in use. This feature is important as the pin is under the vehicle and continuously subjected to the road environment with its frequent hazards. The protective cap is made of a resilient thermoplastic and as such its sheath fits a knurled head of the pin tightly. The sheath of the cap is held captive by a tether attached to a keeper ring that is placed over the pin adjacent to the head. This keeper ring also prevents the pin from rattling between the head and the hitch.
A final object of the invention is the fact that it fits all class II and class III hitches with a 2 inch receiver since the pin diameter and length complies with the industry standard hitch configuration.
These and other objects and advantages of the present invention will become apparent from the subsequent detailed description of the preferred embodiment and the appended claims taken in conjunction with the accompanying drawings.